US2874367A - Highway signalling system - Google Patents

Description

Feb 17, 1959 v J; A. DE PALMA HIGHWAY SIGNALLING SYSTEM l3 Sheets-Sheet 6 Filed Jude 8, 1954 INVENTOR. J.A'. DE PALMA HIS- ATTORNEY Feb. 17, 1959 J. A. DE PALMA HIGHWAY SIGNALLING SYSTEM Filed Jun 8, 1954 15 Sheets-Sheet 7 'INVENTOR. J.A. DE PALMA HIS ATTORNEY Feb. 17, 1959 J. A. DE PALMA HIGHWAY SIGNALLING SYSTEM 13 Sheets- Sheet 8 FIG. 6C.

Filed June 8, 1954 MLS . INVENTOR. J.A. DE PALMA EZMW HIS ATTORNEY Feb. 17, 1959 J. A. DE PALMA HIGHWAY SQIGNALLING SYSTEM 13 Sheets-Sheet 9 Filed June 8, 1954 mm zm mm 2 2 m2 .A Y WM M w mm m E s D H A J .M; QQOE GE 7 mwdE dwdE NQE QQQE 15 Sheets-Sheet 11 HIS ATTORNEY Feb. 17, 1959 J. A. DE PALMA HIGHWAY SIGNALLING SYSTEM' Filed June 8, 1954 NW N M mmilk 1.14, .A S A R m P m o M I D 5 T A I m N w o e w WA E B l w w P m P l l w E m I D )A PM W P J P I llllllllw EH W llr E Y? w 2 E B C L i! i I l e w w Lrmil ll E 7 FIIIIIHII wq m2 llll i E R w A 9 m 1 n F WFNL 2- D l l III A:

Feb. 17, 1959 J. A. DE PALMA HIGHWAY SIGNALLING SYSTEM 15 Sheets-Sheet 13 Filed June 8, 1954 INVENTOR BY J.A. DE PALMA HIS ATTORNEY ilnited States Patent- HIGHWAY SIGNALLING SYSTEM James A. De Palma, Rochester, N. Y.

Application June 8, 1954, Serial N 0. 435,104 15 Claims. (Cl, Mil -31 This invention relates to .a.highway signaling .system for governing automobiletraffic and, moreparticularly, pertains to a system of signaling for a highway divided for opposite directions of trafiic, there being but a single lane for trafiic in each direction except at spaced locations where dual lanes are provided.

It is well known that the ordinary highway having only two traific lanes, one for each .direction, is unsafe with present day congestion of traffic since vehicles travelling in one lane of traific must usethe other lane for passing purposes. Due to this congestion of trafiic and the limitations of ordinary two-lane highways, there is a trend toward the building of four-lane highwayshaving two lanes foreach direction separated by a mall. Such highways are expensive and are efficient only where the traffic is very dense.

Inview of the above considerations and in accordance with the present invention, it is proposed that ahighway having two lanes, one fortraffic in eachdirection, be divided to prevent the passage of traflic between the two lanes. At intervals along each directional lane, it is proposed that dual lanes, or passing lanes, be provided with a signaling system capable of governing traffic speeds by the segregation of vehicles travelling at normal speeds from those travelling at abnormal speeds. It isfurther proposed that the segregation of traflic be such that vev hicles travelling at eitherlow or high speeds are penalized by requiring such vehicles to stop at particular points while vehicles travelling at normal speeds are allowed to proceed unrestricted. Thus, the purposes of thissignaling system are to cause slowspeed vehicles to be stopped at dual lane locations to permit either normal-speed vehicles or fast-speed vehicles to pass them and to cause fast-speed vehicles to be stopped at dual lane locations if such vehicles are exceedingtthe highway. speed limit in approaching such locations.

-More specifically, it is proposed that when a group of vehicles is approaching a dual lane location (conveniently termed a passing siding) that the entrance signals for the two lanes be dark until the first vehicle has entered either of the two lanes. .Upon entering one of the two lanes, the first vehicle, by virtue of its speed classification, determines the aspects to be displayed by the entrance signals for both lanes.

If the first vehicle is travelling at a slow speed it will cause the entrance signals to designate its lane as a slowspeed lane and the other 'lane as a normal-speed lane. Thus, the following vehicles segregate themselves between the two lanes in accordance with the speeds at which they choose to travel. The leaving signal for the slowspeed lane is caused to display a stop indication while the leaving signal for the normal-speed lane is' caused to display a green indication. After the vehicles travelling the normal-speed lane have departed from the dual lane location, the leaving 'signal' for the normal-speed lane is caused to display a stop indication while the leaving signal for the slow-speed lane is caused, after a predeter- "ice mined period of time, to display a green aspect, the slowspeed vehicles being allowed to proceed.

If the first vehicle is travelling at a fast speed in excess of the speed limit, it will cause the entrance signals to designate its lane asa fast-speed lane and the other lane as a normal-speed lane, the entrance signals for the two lanes displaying stop and green aspects respectively. The leaving signal forthe fast-speed lane is caused to display a stop indication for a predetermined period, of time after whichthe signal willpermit the fast-speed car to proceed. However, the arrival of following cars at the normal-speed lane within a predetermined time intervalwill cause the leaving signal for the normal-speed lane todisplay a green aspect while causing the leaving signal for the fast-speed lane to retain a stop aspect until-the following cars have deparated from the normal-speed lane.

With anarrangement of the type proposed above, there is no advantage for any vehicle travelling at high speeds since the overall average speeds of such vehicles will be held to the normal speed range by thejpenaltiesimposed by the signalling system, thus automatically causing highspeed drivers to reduce their speeds to the normal range. Similarly, the penalties appliedto slow-speed drivers tend to cause them to increase their speeds to the normal range. In this way, traflic tends to assume auniform rate of flow which is the'natural basis for obtaining .the maximum carrying capacity for any highway.

An object of this invention is to provide. a systemof signaling for a divided highway having a single lane for traific in each direction and having dual lanes, or passing lanes, spaced at intervals along each directional lane.

Another object of this invention isto provide a signaling system capable of penalizingvehicles travelling at low or high speeds while imposing no penalties on vehicles travelling at speeds within a normal range.

Another object of this invention is to provide a highway signaling system capable of permitting vehicles travel ling at speeds within the normal range to pass vehicles travelling at slow speeds.

A further object of this invention is to provide a highway signaling system having signals located at the entering and leaving ends of dual lane locations along a highway of the type described, such signals being controlled by the detection of traffic and of trafiic speeds by'detection devices.

Another object of this invention is to provide a signaling system for governing traffic at highway intersections, the signaling system being capable of detecting and governing traflic approaching an intersection from any direction.

The feature herein disclosed, which relates to the con trol of highway trafiic at an intersection, is disclosed and claimed in my divisional application Ser. No. 724,372, filed March 27, 1958.

Other objects, purposes and characteristic features of the present invention will be in part obvious from the accompanying drawings and in part pointed out as the description of the invention progresses.

In the accompanying drawings:

Fig. 1A shows diagrammatically a section of a highway at a dual lane, or passing siding, location. Traftic signals and various traific and traffic speeddetection devices associated with the dual lane locationareshown for both directions of traific;

Fig. 1B shows a section of a highway organized to in clude a plurality of the dual lane locations shown in detail in Fig. 1A;

Figs. 2A-2G show a dual lane location for one direction of highway trafiic and trace the sequence of traffic signal aspects in relation to the movements of a slowspeed car through the highway section;

Figs. 3A-3G show a dual lane location for one direction of highway traffic and trace the sequence of trafiic signal aspects in relation to the movements of a normalspeed car through the highway section;

Figs. 4A-4G show a dual lane location for one direction of highway traffic and trace the sequence of traflic signal aspects in relation to the movements of a fast-speed car through the highway section;

Figs. 5A-5G show a dual lane location for one direction of highway traflic and trace the sequence of traffic signal aspects in relation to the movements of a slowspeed car followed by another car which prefers to travel at a faster speed;

Figs. 6A-6D show diagrammatically the various traffic signals, detection apparatus and operating circuits for a dual lane location for one direction of highway traflic;

Fig. 7 is a layout plan showing the way in which Figs. 6A-6D are related and must be correlated to present the complete circuit and apparatus layout for a dual lane location for one direction of highway traffic;

Fig. 8 shows a highway intersection along with various trafiic signals and traffic detection devices; and

Figs. 9A-9C show diagrammatically the various trafiic signals, detection apparatus and operating circuits for a highway intersection signaling system.

In order to simplify the illustrations in the drawings and facilitate in the explanation of the fundamental characteristics of the invention, various parts and circuits have been shown diagrammatically in accordance with conventional symbols. Arrows with associated symbols and are employed to indicate connections of the circuits of the various relays and other apparatus to the opposite terminals of a suitable source of energy for the energization of such relays and apparatus; and the source of energy may "be of any suitable characteristic for the purpose intended. The various contacts of the relays involved in the illustrations are shown conventionally as being in a lower or inclined position when the coil or winding of the associated relay is deenergized, and in a raised or horizontal position when the relay is energized; the contacts belonging to any given relay are shown connected to its coil or winding by dotted lines, and these contacts may be either below or above the illustration of the relay winding. The front and back contacts between which the movable contacts are operated by the dilferent relays are shown conventionally as arrowheads, and the movable contacts are ordinarily of the type which have their contacts pulled downwardly by gravity or by spring action.

Referring now to Fig. 1A, a section of an east-west highway is shown. The highway is assumed to consist of a single lane EL for east-bound traffic and a single lane WL for west-bound traffic, the lanes EL and WL being separated by a barrier or mall to prevent the passage of traffic between the two lanes. Arrows indicate the direction of traffic movement through the highway.

At an intermediate point along the directional lane EL a dual lane, or passing siding, location is shown, the lanes being identified as Eastbound Main and Eastbound Siding. A barrier separates the Eastbound Main from the Eastbound Siding to prevent the passage of traffic between the two lanes. The purpose of the dual lane location is to permit cars to safely pass other cars travelling at speeds below or above the normal range for the highway.

A'similar dual lane location is shown along the westbound lane WL.

It is assumed that a number of similar dual lane locatrons are provided along the highway (see Fig. 1B), the number and lengths of such locations being dependent upon trafiic conditions for the highway.

Since all dual lane locations can be considered identical from functional and operational standpoints, further description can be confined to the dual lane location for east-bound traffic, the dual lanes being referred to as the main and the siding.

An electrical circuit network is provided for a dual lane location. The circuit network is actuated by various detection devices and serves to control the aspects displayed by various traffic signals.

Two approach speed detection devices ASD1 and ASD2 are located in the highway EL on the approach to the dual lane location. The distance between the detection devices ASD1 and ASD2 is arbitrary and is dependent upon the speeds normally encountered on the highway. Similarly, the relative distance between the detector ASD2 and the dual lane location depends on the range of speeds encountered. It is assumed that the detectors ASD1 and ASD2 are of the treadle type, although photo-electric cells or other electronic devices can be employed.

As cars pass over the detectors ASD1 and ASD2, the electrical network is actuated, the circuit network being capable of assuming and storing a description of the speed range into which the cars fall. Only one speed description per group of cars can be stored in the circuit network; and since the first car is assumed to be pacing the group, the speed of the first car only is detected.

After a predetermined time interval, the circuit network can detect and store a speed description for another group of cars. However, it is further assumed that the time interval is such that no conflict "between speed dcscriptions can result from the over-taking of one group of cars by another group at the dual lane location. In other words, if the spacing between successive groups of cars is great enough to permit the circuit network to store two speed descriptions, then the first group of cars is assumed to leave the dual lane location before the second group enters the location.

Two color light traffic signals MEG and SEG are located at the entrance of the main and the siding, respectively. The signals MEG and SEG govern trafiic entering their respective lanes. Under initial conditions of operation (i. e. no cars occupy the dual lane location), the signals MEG and SEG are dark, it being assumed that dark signals impose no restrictions on traffic movement so that the first car approaching has a choice of entering either the main or the siding lane.

The entrance signals MEG and SEG are controlled by the circuit network in accordance with the speeds detected by the, detectors ASD1 and ASD2.

A main entrance detector MEDI is provided at the entrance to the main to detect cars entering the main, a similar detector SED1 being provided at the entrance to the siding. The detectors MEDl and SED1 are of the same type previously described for the detectors ASD1 and ASD2, and, when occupied by cars, cause the circuit network to control the normally dark signals MEG and SEG to display lighted aspects.

To summarize the preceding description: As a group of cars approaches the dual lane location, the speed of the first car is detected and stored in the circuit network through the action of the detectors ASD1 and ASD2. The entrance signals MEG and SEG present dark aspects to the approaching group of cars indicating that either the main or the siding can be entered. Regardless of which route is chosen by the first car, the entrance signals MEG and SEG are caused to display a lighted aspect when the first car occupies either of the entrance detectors MEDl or SED1.

The aspects displayed by the signals MEG and SEG are determined by the speed of the first car in-the group and govern the following cars in the group insofar as to which route they take. In other words, the other cars are directed either to follow the first car or to take the alternate lane to pass the first car. If the first car is detected as a normal-speed car, the signals MEG and SEG direct the remainder of the cars to follow the first car; but if the first car is detected as a fast-speed Or a slow to take the'alternate lane to escape signalingpenalties to be described which 'are applied to cars travelling at speeds below or abovethe normal range.

If the first car is a normal-speed car, the signals MEG and SEG each display an illuminated aspect until the first car passes a second entrance detector MED2 or SEDZ; and the signals then return to a dark condition.

If the first car is a slow-speed or a fast-speed car the signals each display an illuminated aspect until the first car leaves the dual lane location; the signals then returning to a dark condition.

The second main entrance detector MEDZ is located in the main to detect the .passage oftrafiflc. The detector MEDZ is of the type previously described and functions primarily to cause the transfer of stored speed descriptions through the electrical circuit network for. the control of a main leaving signal MLG, the similar detector .SEDZ and a similar leaving signal SLG being. provided for the siding.

The leaving signals MLG and SLG display stop, or red, aspects normally. .Proceed, or green, aspects are controlled by the circuit network after the second entrance detector MED2 or SEDZ for a route is occupied. A'first car travelling at a normal speed through the main causes the main leaving signal MLG to display a green aspect, the siding leaving signal SLG continuing to. display a red aspect. Similarly, a normal-speed first car choosing .to travel through the siding causes the signal SLG to. display a green aspect when the car passes over the detector SED2; and the leaving signal MLG continues to display a red aspect.

If the first car is a slow-speed or a fast-speedcar choosing to travel over the main, the detection of the car by the detector MED2 causes a timing device to operatein the circuit network; and the leaving signal MLG displays a red aspect until the timing device has completed its operation. In other words, a predetermined time penalty is applied to cars travelling at;speeds above or below the normal range. The subsequent passing of the siding entrance detectorSEDZ by the remainder of the cars 'in the group causes the timing device associated with the main leaving signal MLG to be inoperative and causes the leaving signal SLG to display a green aspect. The signal SLG continues to display a green aspect until all of the remainder of the cars in the group leave the dual lane location, their departure being detected by a leaving detector SLD of the type previously described. After the cars travelling over the siding have departed from the dual lane location the signalSLG revertsto displaying a red aspect and the timing device associated with the signal MLG operates to cause the ultimate displaying of a green aspect by the signal MLG. The first car then leaves the main causing the signal MLG to become red when the car passes over a detector MLD of the type previously described, the entrance signals MEG and SEG being returned to a dark condition. Similar operational effects are producedregardless of which route, the main or the siding, is chosen by the first car or cars.

A main violation detector MVD is located in the main to detect cars passing the leaving signal MLG in violation of that signal. If a car passes the signal MLG while the signal displays a red aspect, the detector MVD in conjunction with the circuit network can cause a camera, spray gun, or other device to be actuated to indicate a signal violation by the car. A similar detector SVD is provided for the siding. v

To further describe the operations of the various traflic signals in response to the passing of detection devices by trafiic, reference is made to Figs. 2A-2G which trace the movement of a slow-speed car through a dual lane location. In the Figs. 2A-2G the dual lane location is represented diagrammatically along with the various detection devices and signals. The detection devices are represented by dots while the signals are represented by circles containing reference characters which indicate the aspects dark D, red R, yellow Y, and

green G displayed by the signals. For simplicity, reference characters are assigned to the detection devices in Fig. 2A only.

In Fig. 2A, a slow-speed car SC is shown approaching the speed detectors ASD1 and ASD2. The entrance signals MEG and SEG display dark D aspects while, the leaving signals MLG and SLG display red R aspects.

1 When the slow-speed car SC passes over the detectors ASD1 and ASDZ (see Fig. 2B) no change occurs in the aspects displayed by the varioussignals, although a speed description is assumed and stored in the electrical circuit network associated with the. dual lane location.

It is assumed that the slow-speed car SC chooses to pass through the dual lane location via the main. When the car-SC passes overthe entrance detector MEDl (see Fig. 2C) the circuit network causes the main entrance signal MEG to display a yellow aspect while the siding entrance signal SEG is caused to display a green aspect. At this point, a following car is presented with the choice of either following the slow-speed car SC with the warning that-it will be restricted at the leaving end of the main or taking the route over the siding to pass the slow-speed car SC with no restriction.

Further progress of the car SC over the detector MED2 (see Fig. 2D) causes no further change in the aspects displayed by the signals. However, the speed description stored for the slow-speed car SC is transferred in the circuit network and a timing device is actuated. The main leaving signal MLG cannot be controlled by the transferred speed description to display agreen aspect until the timing device completes its operation. 7

In Fig. 2E the slow-speed car SC 'is shown at an intermediate point during its progress through the main. The timing device previously actuated by the car SC has completed its operation causing the main leaving signal MLG to display a green aspect. v

, .When the car SC passes over the main leaving detector MLD (see Fig. 2F) the entrance signals MEG and SEG are caused to display dark aspects. The leaving signal MLG continues to display a green aspect until the car SC leaves the dual lane location.

In Fig. 26 the slow-speed car SC is shown after leaving the dual lane location. The entrance signals MEG. and SEG display dark indications while the leaving signals MLG andSLG display red indications, such being the normalconditions for the signals. The speed description stored for the car SC in the circuit network is cancelled when the car SC completely passes the leaving detector MLD.

Similar signal and circuit operations can be. described for a slow-speed car SC choosing to travel through the siding rather than the main.

The progress of a car travelling through a dual lane location at a normal speed is traced in Figs. 3A-3G, the representation'of thevarious signals and detectors being as previously described in Figs. 2A-2G.

In Fig. 3A a normal-speed car NC is shown approaching the detectors ASD1 and ASDZ. The entrance signals MEG and SEG display dark aspects while the leaving signals MLG and SLG display red aspects.

When the normal-speed car NC passes over the detectors ASD1 and ASDZ (see Fig. 38) no change occurs in the aspects displayed by the signals although a speed description is assumed and. stored in the circuit network associated with the dual lane location.

Assuming that the car NC chooses to enter the main and occupies the detector MEDl (see Fig. 3C), the entrance signal MEG is caused to display a green aspect while the entrance signal SEG is caused to display a red aspect. At this point any following cars are directed to follow the normal-speed car NC and are restricted from attempting to pass the normal-speed car by entering the siding. This condition is in keeping with the safety conditions prescribed for the highway in that no car should attempt to pass a car travelling at a speed within the normal range.

When the car NC passes over the detector MED2 I (see Fig. 3D) the speed description stored in the circuit network is transferred causing the main leaving signal MLG to display a green aspect. The entrance signals MEG and SEG are caused to revert to their normal condition of displaying dark aspects. The reason for such a mode of signal operation will become evident when a description of circuit network operation is disclosed.

In Fig. 3E the normal-speed car NC is shown at an intermediate point along the main, the signal aspects remaining unchanged.

As the normal-speed car NC passes over the leaving detector MLD (see Fig. 3F) no change appears in the aspects displayed by the signals; but when the normal speed car NC completes its passage over the detector MLD (see Fig. 3G) the speed description stored in the circuit network for the car is cancelled and the main leaving signal MLG is caused to display a stop indication.

The progress of a car travelling at a fast speed is traced in Figs. 4A-4G, the various signals and detection devices being represented as previously described for Figs. 2A-2G. 1

In Fig. 4A a fast-speed car PC is shown approaching the detection devices ASD1 and ASDZ. The entrance signals MEG and SEG display dark indications while the leaving signals MLG and SLG display red indications.

When the car FC passes over the detectors ASD1 and ASD2 (see Fig. 4B) no change occurs in the aspects displayed by the signals although a speed description is assumed and stored in the circuit network associated with the dual lane location.

Assuming that the car FC chooses to enter the main and occupies the detector MEDl (see Fig. 4C), the entrance signal MEGis caused to display a red aspect while the siding entrance signal SEG displays a green aspect. At this point a following car is directed to enter the siding to escape a signalling penalty which will be imposed on the fast-speed car FC.

In Fig. 4D the fast-speed car PC is passing the detector MED2. No change occurs in the aspects displayed by the signals; but the speed description stored for the fast car is transferred in the circuit network and a timing device is actuated. The main leaving signal MLG cannot display a green aspect in response to the transfer of the speed description until the timing device completes its operation.

In Fig. 4E the fast-speed car PC is shown at the leaving end of the main. It is assumed that the timing device previously actuated by the passage of the car over the detector MED2 has completed its operation causing the leaving signal MLG to display a green aspect. It is assumed that the operating time of the timing device is such that a fast-speed car is forced to stop by the signal MLG before the car can proceed upon a subsequent clearing of the signal. In this manner, cars travelling at speeds above the normal range are held to a normal speed average through the highway.

When the fast-speed car is passing over the leaving detector MLD no change occurs in the aspects displayed by the signals (see Fig. 4F). After the fast-speed car FC completes its passage over the detector MLD (see Fig. 46) the speed description stored in the circuit network is cancelled and the signals assume their normal aspects.

In Figs. 5A-5G a slow-speed car SC followed by another car NC desiring to travel at a normal speed is shown travelling through the dual lane location, the various signals and detection devices being shown as previously described for Figs. 2A-2G. In Fig; 5A the slow-speed car SC is shown passing over the detectors ASD1 and ASD2. The entrance signals MEG and SEG display dark aspects while th'e leaving signals MLG and SLG display red aspects. A speed description for the slow car SC is assumed and stored in the circuit network associated with the dual lane location; and this speed description applies also to the following normal-speed car NC. In other words, the two cars SC and NC are described to the circuit network according to the speed category into which the first car falls.

Assuming that the slow-speed car SC chooses to-enter the main, the entrance signals MEG and SEG are caused to display yellow and green aspects, respectively, when the slow car SC passes over the entrance detector MEDl. The normal-speed car now has a choice of routes in that it may accept the green signal SEG to pass the slow-speed car or it may accept the yellow signal MEG to follow the slow-speed car with the warning that a signaling restriction is to follow.

Assume that the normal-speed car chooses to enter the siding and pass the slow-speed car SC. When the slowspeed car SC passes over the detector MED2 the speed description stored in the circuit network is transferred and the timing device associated with the leaving signal MLG is actuated. The arrival of the normal-speed car NC on the siding entrance detector SED2 (see-Fig. 5C) causes no change in the aspects displayed by the entrance signals MEG and SEG, but causes the siding leaving signal SLG to display a green aspect. Furthermore, the timing device actuated by the slow-speed car SC is caused to cease operation by the passage of the normal-speed car NC over the detector SED2. In this manner, the main leaving signal MLG is prevented from displaying a proceed aspect until the normal-speed car NC completes its passage through the siding.

In Fig. 5D both the slow-speed car SC and the normalspeed car NC are shown at intermediate points in the dual lane location, no change occurring in the aspects displayed by the signals.

As the normal-speed car leaves the siding (see Fig. 5E) and passes over the leaving detector SLD no change occurs in the apsects displayed by the signals. However, when the normal-speed car NC leaves the dual lane location (see Fig. 5F) the timing device associated with the main leaving signal MLG is allowed to operate, resulting in the ultimate clearing of the signal MLG. The slow-speed car is allowed to leave the main and pass over the main leaving detector MLD causing theentrance signals MEG and SEG to revert to displaying dark aspects, the speed description stored in the circuit network being cancelled.

In Fig. 5G the slow-speed car is shown after leaving the dual lane location, the signals having returned to th normal condition. 4

Having described a dual lane location and the mode of operation of the various signals and detection devices, a specific description of the circuit network associated with the dual lane location and the various signals and detection devices can be given.

In the circuit drawings of Figs. 6A-6D, the various detection devices are shown in block form, specific regard being given only to the contacts associated with each detection device. Since it is assumed that the detection devices are of the self-restoring treadle type, the detector contacts are shown normally open; and the assumption 18 made that such contacts are closed only at times when cars are on the detection devices.

Speed detection As the wheels of cars pass over the detector ASD1, a detection relay AD is alternately energized and deenergized in response to successive closings and openings of a contact 1 of the detector ASD1. In other words, the relay AD is energized whenever the wheels of a car are on the detector ASD1 and is deenergized whenever the detector is unoccupied.

When the relay AD is energized, a detection repeater relay ,ADP ;is.energized by. .a pick-up circuit. including. .a front..contact;.2.lof,relay The relay ADP ,is made, slow-acting by the connection of a resistor andja capacitor 3 in: parallel with therelaywinding ADP. It ,isintended that the relayADRbe energized .Whenthe first car in a group .pa'sses .over .the. detector ASD1, and deenergized after. the lastcar. inlthe, group .passesthe detector. In this manner, a successive energization and deenergization ofjthei relayADP indicates the passage of a distinct grouppf cars; and a subsequent energization of the relay indicates. thearrival of another groupv of. cars. Thus, the sloiwfacting, characteristics. of the; relay ADP must be such thattheminimum release timeof .the relay must be longer, .than ,the. .timeintervals between. successive occupancies of the detector ASD1 bythe wheels of the cars in aigroup. Thejm'aximum release time. of the relay ADP must be less than the time intervalbetwen the, passing of,,the, detector ASD1 by the.v last car in one group and the arrival on .the detector by the first car in a following group if therelay. ADP is todete'ctjtwo separate groups ofrcarsh In otherwords, the circuit constants aifecting the release time. of relay ADP are determinedby speed and distance. considerations. for. a given. highway...

To detect thespeed of a car, and to storera speeddescription for the car, two speed detection relays' ND and FD are provided 'along. with three'speed description relays. S, N,.and F.;. The normal-speed detection relay ND is normally energized by a pick-up circuit including. a back contact 4 ofrelay. ADP;;and. the relay. ND is made. slow-acting, by a resistor. and a capacitors connectedin parallel withxthe relayrwindinglND. The fast-speed de.-' tection relay PD is normally energized. by a pick-up cir-. cuit, includinga back contact 6 'of. relay ADP; .and1'the relay. PD is made. slow-acting by a resistoranda capacitor .7 connected in parallel lwiththerelay winding FD. The, slowspeed description relay1S is energizedby a pick up circuit extending fromv including a contact 8 of they detector ASD2, a back. contact 9 ofrelay ND, aback contact10 of relay FD, the, relay. .WindingS, a back contact 11 ,of relay.N,.and a back contact 12 of relay F, to An alternate pick-up circuit for the relay S extendsfrom including contact'8 of detector ASD2, a back contact 13,01? relay ADP, a front contact 140i relay ND, a front contact 15 of relay FD, the relay winding S, the, back; contact 11, ofirelay N, and the back contact 12 of relay F, to The normal speed'description relay N is energizedby .a pick-up circuit extending from including ajicontact 16 of detector ASD2, a front contact 17 of; relay ND, a backfcontaet 18 of relay FD, a back contact 19. of relay S, .the relay winding N, and a back contact 20 of relay F,. to' The fast-speed descripe tionrelay F is energizedby a pick-up. circuit extending from including a contact 21 vof detector ASD2, a frontfcontact 2-2 of relay. ADP, a front contact 23 of relay ND, a front. contact 24 of relay FD, a back contact '25 of relay S, a back contact 26 of relay N, and the relay winding F, to

It can be seen from the preceding circuit description that in .order to energize one of the speed description relays S, N or F, a car must occupy the detector ASD2. A selection is made with regard to which relay S, N or F is to be energized, the selection being dependent upon the state of the detection relays ND and FD (i. e. whether the relays ND and FD are energized or deenergized) at the time whenthe car occupies the detector ASDZ. In order to specifically select one of the relays S, N or F, the release time of the relay ND must be longer than the release time of the relay FD; and the release time of the relay ADP must be greater than that of either relay ND or FD.

More specifically, when a fast-speed car passes over the detector ASD1, the relay ADP is energized, the back contacts 4 and 6 of relay ADP opening the pick-up cir cuits for the speed detection relays ND and FD, respectively. When the fast-speed car occupies the detector.

thedetector ASD2. Once energized, therelay F is heldenergized by a stick circuit extending from (+),-includ; ing a front contact 27 of .relay ADP, a front contact 28 of relay F,.and1the relay winding F, to Since the release time of the relay ADP determines theidentifica; tion of separate groups of cars, any following cars occupying the detector ASD1 before the relay ADP releases its armatureare. identified as parts of a group including the fast-speedcar described bytherelay F.

When, a normal-speed car passes the detector ASD1, and arrives. on the detector ASD2, the pick-upcircuitfor the speed description relay N must beclosed. For this to occur, front contact 17- of. relay ND and back contact 18 of relay FD mustalready be closed when the car,oc-. cupies thed'etectorASDZ. Thus, the time required for a normal-speed 'car. to travel. from the. detector ASD1, to, the detector ASD2 must be less than the release time ofthe relay ND and greater than the release time of the relayFD. Once energized, the relay N is held energized by a stick circuit extending from including a front contact29 of relay ADP, a front contact 30 of relay N, the relay winding,N, and :back contact 20 of relay F, to Any following cars arriving on the. detector ASD1. withinthe release time of the relay ADP areidentified as.-

parts of a group including the normal-speed car described by the relay Nb;

When a slow-speed car passes the detector ASD1 and arrives on 'the detector ASD2, the pick-up circuit for the speed description relay 8 must be closed. Under normal conditions, the relayS is energized by the pick-up circuit including a back contact 9 of relay ND and back contact 10 of relay FD. Thus, the time required for a slow-speed car to travel from detector ASD1 to detector ASDZ must be greater than the release times of either relayv ND or FD. Iffhowever, the distance between the detectors is greater than the length of a car and a slow speed car should either stop between the detectors or. cove'r'the distance at an abnormally slow speed, the time of transit. of the car might exceed the release time of the.

held energized. by a stick circuit extending from includingeither a back contact31of relay AD or a front contact 32 of relay 'ADP a front contact 33 of relay S, thejrelay' winding S, back contact 11 of relay N, and back contact 12 of relay F, to

Since under normal conditions, the relay S is held energizedtby. the. stick circuit including front contact 32 of'relay ADP, any following cars arriving on the detector-ASD1 withinthe release time of the relay ADP are identified-as parts of a group including the slowspeed car described by the relay S. Under the abnormal conditions previously described, 1 whereby a car either stops or travels very slowly between the detectors ASD1 andASDZ, the transit time of the car exceeding the releas'e'time of therelayADP, the relay S, once ener1 gized, is held energized by a stick circuit including the back contact 31 of relay AD. Under these conditions, the subsequent'arrival 'of another car on the detector ASD1; caus'es thedeene'rgization of the relay 8' by the opening of. back contact 31 of relay AD in the stick circuit, the second car causing its own speed description to be established.

The contact 16 of detector ASD2 is assumed to be slow-acting to the extent that, once closed, it does not reopen for a time interval equal to the crossover time of the relay FD (i. e., the time between the opening of the front contacts and the closing of the back contacts of the relay). The purpose of the slow-acting feature is to insure the establishment of a speed description for a car travelling at a critical speed which is at the borderline between the normal and fast speed categories. Should such a car pass over the detector ASD2 at a time when the relay FD is dropping away its armature, the pick-up circuits for the relays F and N are both open because front contact 24 of relay FD is open in the pick-up circuit for relay F and back contact 18 of relay PD is not yet closed in the pick-up circuit for relay N. Thus, contact 16 of detector ASD2 must remain closed until back contact 18 of relay FD closes to energize relay N; otherwise, the passage of the front wheels of the car over the detector ASD2 might fail to establish a normal-speed description.

Similarly, the contact 8 of detector ASD2 is slowacting to bridge the crossover time of the relay ND. In this instance, a car travelling at a critical speed which is at the borderline between the slow and normal speed categories is assured of establishing a slow-speed description by causing the energization of relay S.

To prevent the energization of more than one speed description relay at a time, the pick-up circuits for each of the relays S, N and F include back contacts of the other two relays. For example, when relay S is energized, its two back contacts 19 and 25 open the pickup circuits for relays N and F, respectively.

Initial storage of speed descriptions As previously described, a speed description indicated by the energization of one of the relays S, N or F is assumed by the circuit network when a car, or group of cars, passes over the detectors ASD1 and ASD2. It is intended that once a speed description is established for a car or group of cars, the description is to be maintained in the circuit network until the car (or cars) leaves the dual lane location. It is further intended that provisions be made for the storage of speed descriptions for more than one group of cars. This is considered desirable for any highway in which the distance between the detector ASD2 and the dual lane location may be large in comparison to the length of the dual lane location. In other words, on some highways several groups of cars may be contained in the stretch of highway between the detector ASD2 and the dual lane location; and a separate speed description is stored for each group of cars.

In order to provide for the storage of a plurality of speed descriptions for groups of cars approaching the dual lane location, relays S1, N1 and F1 are provided for one description storage while relays S2, N2 and F2 are provided for another description storage. The relays S1, N1 and F1 are, in effect, repeaters of the relays S, N and F, respectively; and the relays S2, N2 and F2 are, in effect, repeaters of the relays S1, N1 and F1, respec tively. Speed descriptions are passed from one relay group to the next by a circuit means to be described.

A relay SNF is provided to indicate that a speed de scription is assumed for a group of cars and that the description is ready to be transferred to the first bank of description relays S1, N1 and F1.

A slow-acting description stick relay DS is provided to indicate that a speed description is completely transferred to the relays S1,'N1 and F1.

A relay SNFS is provided to indicate that a speed description is available for transfer and that the transfer is initiated. The relay SNFS also functions to preclude repeated transfers of the same speed description for one group of cars. a

A transfer relay TN1 is provided to accept the transfer of a description to the first bank of description relays S1, N1 and F1 only when no description is already stored in those relays.

A slow-acting description stick relay D81 is provided to accept a speed description transferred to the first bank of description relays S1, N1 and F1 and to hold the description stored in those relays until it can be transferred to the second bank of description relays S2, N2 and F2. The relay DSl also functions to initiate the transfer of a speed description from the relays S1, N1 and F1 to the relays S2, N2 and F2, respectively.

Another transfer relay TN2 and another slow-acting description stick relay DS2 are provided to function in the manner described for the relays TN1 and D81 respectively, the relays TN2 and D82 being associated with the transfer and holding of speed descriptions applied to the relays S2, N2 and F2.

More specifically, assume that the relay S is energized by the detection of a slow-speed car passing over the detectors ASD1 and ASD2. The relay SNF is energized by a pick-up circuit extending from including a back contact 34 of relay TN1, a back contact 35 of relay SNFS, a front contact 36 of relay S, and the relay winding SNF, to It is obvious from the circuit diagram that front contacts 37 and 38 of relays N and F, respectively, connected in parallel with front contact 36 of relay S provide for the energization of the relay SNF whenever any of the speed ranges are detected for a car. Once energized, the relay SNF is held energized by a stick circuit extending from including a front contact 39 of relay DS, a front contact 40 of relay SNF, and the relay winding SNF, to

The energization of the relay SNF results in the subsequent energization of the relays SNFS and TN1.

Relay SNFS is energized by a pick-up circuit extending from including a front contact 41 of relay S, a front contact 42 of relay SNF, and the relay Winding SNFS, to A stick contact 43 of relay SNFS closes to maintain energization of relay SNFS as long as front contact 41 of relay S is closed. The back contact 35 of relay SNFS opens the pick-up circuit for relay SNF and holds that pick-up circuit open as long as the relay SNFS is energized, the relay SNF remaining energized through its stick circuit. It is obvious that the relay SNFS can be energized in a similar manner by either a front contact 44 of relay N or a front contact 45 of relay F, the front contacts 44 and 45 being connected in parallel with front contact 41 of relay S.

The relay TN1 is energized by a pick-up circuit extendmg from including a front contact 46 of relay SNF, a back contact 47 of relay D81 and the relay windng TN1, to a front contact 48 of relay TN1 closmg a stick circuit for that relay.

The relay D51 is then energized by a pick-up circuit extending from including a front contact 49 of relay TN1, a back contact 50 of relay TN2, and the relay winding D81, to A front contact 51 of relay DSl closes one stick circuit for relay DSI, while a front contact 52 of relay DS1 closes a second stick circuit which includes a back contact 53 of relay D52. At this time, the normally energized relay DS is deenergized by the opening of the back contacts 54 and 55 of relays TN1 and DSl, respectively. However, since the relay DS is slowacting, its front contacts remain closed long enough to allow the energization of the slow-speed description relay S1 by a pick-up circuit extending from including front contact 56 of relay S, a front contact 57 of relay SNF, a front contact 58 of relay SNFS, a front contact 59 of relay DS, a front contact 60 of relay TN1, a front contact 61 of relay D51, and the relay winding S1, to A front contact 62 of relay S1 closes a stick circuit for the relay S1 including a front contact 63 of relay DSl. The transfer of a slow-speed description from relay S to relay S1 is now completed; and it is obvious from the circuit diagram that similar pick-up and stick circuits are l3 P i q re ay N n to allow s mi a rafisfer of normal-speed and fast-speed descriptions.

When the slow-acting relay DS releases its armature the relay SNF is deenergized by the opening of front contact 39 of relay DS in the stick circuit of relay SNF. The pick-up circuit for relay, S1 is opened simultaneously by front contact 59 of relay DS; but relay S1 remains energized through its stick circuit. The deenergization, of relay SNF results in the deenergization of relay TN1 by the opening of front contact 46 of relay SNF in the stick circuit of relay TN1, the pick-up circuit of relay TN1 being already opened by back contact 47 of relay DS1. The opening of front contact 42 of relay SNF makes relay SNFS dependent upon its stick circuit for energization; and relay SNFS remains energized until relay S is deenergized. a H t The deenergization of relay TN1 causes-theenergization of relay DS by the closing of back contact 54 of V relay TN1.

energization of relays D81 and S1.

If another speed description is now assumed by the relays S, N and F, the relays SNF and SNFS are energized as previously described. However, the speed description cannot be transferred into the first bank of relays S1, N1 and F1 because the pickup circuit for the transfer relay TN1 remains opened by back contact 47 of relay DSl. Thus, the storage of more than one speeddescription in the bank of relays S1, N1 and F1 is impossible.v

Returning now to the slow-speed description stored by the relay S1, When relay TN1 becomes deenergized the relay TN2 is energized by a pick-up circuit extending from including a back contact 64 of relay,TN 1, a frontcontact 65 of relay D51, a back contact 66 of relay D82, and the relay winding TN2, to a stick circuit for relay TN2 being closed-by a front contact 67 .of relay TN2. The back contact 50 of relay TN2 opens one, of the two stick circuits for relay DSl.

Relay D52 is now energized (see Figs. 6A and 6B) by a pick-up circuit extending from including a front contact 68 of relay TNZQawire 69, a front contact 70, of a relay SBP, a front contact 71 of a relay MBP, a wire 72, and the relay winding DS2, to A front contact 73 of relay DS2 in parallel with frontcontact 68 of relay TN2 closes to establish a stick circuit for relay DS2.

Back contact 53 of relay DS 2 opens the effective stick' circuit for relay DSl. However, the slow-acting characteristics of relay DSl prevent the opening of its front contacts 63 and 65 which, respectively, are maintaining the energization of relaysSl and TN2. Thus, the slowspeed description is transferred from relay S1 to relay S2 upon the energization of relay S2 by a pick-up circuit extending from including front contact 74 of relay S1, front contact 75 of relay TN2, a front contact 76 of relay DSZ and the relay winding S2, to A stick circuit for relay S2 which includesfront contact 77 of relay S2 and front contact 78 of relay D82 is closed.

When the slow-acting relay 1381 does releaseits' armature, relay S1 is deenergized by the opening of its stick circuit by front contact 63 of relay DSI. Relay TN2 also is deenergized by the opening of front contact 65 of relay DSl.

'The slow-speed description is now stored by relay S2 in the second bank of speed'description relays. It is obvious from the circuit diagramthat a normal-speed or a fast-speed description can be transferred from relay N1 or F1 to relay N2 or F2, respectively, by circuits similar to that described for the transfer from relay S1 to relay S2.

At this time, another speed description can be transferred into the first bank of description relays S1, N1 and F1 because the pick-up circuit for relay TN1 is closed by back contact 47 of relay DSl. It is relevant to note that. back contact 66 of relay DS2 in the pick-up circuit No further transfer of the slow-speed description occurs untilv the first car in the group identified by the description enters either the main or the siding in the dual lane location.

Storage, transfer and utilization of speed descriptions for the control of entrance signals The utilization of speed description storages for the control of the entrance signals MEG and SEG at the dual lane location can be described in view of the preceding description of speed detectionmeans and the means for the initial storages and transfers of speed descriptions.

Referring now to Fig. 6B, two detection relays MEI and SE1 are provided to indicate the passage of cars enter-- ing the main and the siding, respectively. The relaysMEl. and SE1 repeat operations of the entrance detectors MEDl and SEDl, respectively, in response to the passage:

of traffic.

A A bank of three speed description relays MS, MN and.

MP is provided to store speed information associatedwith a group of cars when the firstcar in the group chooses;

to enter the main. A similar bank of relays SS, SN and SF is provided'to store speed information when the first car in a group chooses to enter the siding. Only one of the two banks of relays can store a speed description at any given time, each bank functioning, in effect, asa repeater of the bankof speed description relays S2, N2

speed description. in that bank of relays.

be operative at one time.

Two back repeater relays MBP and SBP are provided to indicate. the storage of a speed description in therelay. banks associated with the main and the siding, respectively. The relay MBP is, in efiect, a back contact repeater of the speed description relays MS, MN and MF, while the relay SBP repeats the relays SS, SNand SF.

A back repeater stick relay BPS is. provided as an inverse repeater of the relays MBP and SBP. The relay BPS functions to allow the storage of a speed description in the bank of relays S2, N2 and F2 after a previous description is transferred out of that bank of relays.

More specifically, assume that the slow-speed description previously described is stored in the relay S2, the relays S2 and D82 being energized by their respective stick circuits. 7 group identified by the slow-speed description chooses to enter the main at the dual lane location.

. When the first car, occupies the main entrance detector MEDl, the relay MEI is energized. by the closing of a contact 79 of detector MEDl.

The relay MES is then energized by a pick-up.circuit (see Figs. 6A and 6B) extending from including a front contact 80 of relay S2, a wire 81, a front contact 82 of relay MEI, the relay winding MES, and a back .contact 83 of relay SES, to

Upon the energization of relay MES, relay MS becomes energizedby a pick-up circuit extending from including a front contact 84 of relay S2, a wire 85, a front contact 86 .of relay MBP, a front contact 87 of relayMES, and the relay winding MS, to A stick circuit is closed for the relay MS by a front contact Assume also that the first car in the

Images